When, while a memory card mounted with a non-volatile rewritable memory is being accessed (for data read, data write or data deletion), the power supply for the memory card is suddenly interrupted, the data already stored in the memory card may also be destroyed. Such data destruction in a memory card may possibly occur also when the memory card is not being accessed by any user depending on control by a controller included in the memory card. A technique for inhibiting such data destruction in a memory card has been known in which a large-capacity capacitor (hereinafter referred to as a “backup capacitor”) is provided for use as a backup power supply in case the power supply is interrupted (see, for example, patent literature 1).
With a backup capacitor provided, even when the power supply for a memory card is interrupted, the memory card can be kept powered for a period of time corresponding to the amount of electric charge stored in the backup capacitor. By having a normal termination process executed by the memory card itself while the memory card is powered by the backup capacitor, the data stored in the memory card can be prevented from being destroyed.